1. Technical Field
The present disclosure relates generally to securely erasing data and more specifically to techniques and systems for securely erasing data in copy-on-write file systems.
2. Introduction
Electronic devices capable of storing information generally include a storage device such as a hard drive. The programs and data stored on the storage device are based on a file management system. In some file management systems such as a copy-on-write file system, new copies of files storing programs and data are created and stored in blocks of the storage device whenever a change is made to the file. By storing multiple copies of the same file, the file management system can fall back on older versions of the file when problems arise with the current copy of the file, thus improving the robustness of the system in case of a system crash. For wearable storage devices such as solid state drives, writing a new copy of the file whenever changes are made helps dissipate wear evenly to blocks of the storage device, thus improving its longevity and reliability.
There are however disadvantages to this type of file management system. For instance, storing multiple copies of a file can make the file (and as a result, the electronic device) more prone to attack. As an example, an attacker can access a version of a file that the user has deleted by gaining access to older copies of the file.
Thus, there is a need for improved techniques to securely erase data in copy-on-write file systems.